'To like' is a transitive verb. This means it needs a direct object and doesn't make sense without one. Intransitive verbs don't take a direct object and can make sense alone. Verbs of movement are always intransitive. Verbs expressing sentiment 'like', 'love',' hate', are transitive you need to say what or who you love, like, hate. When the object is impersonal or abstract we use 'it'. In your example 'it' refers to where the speaker is.

pinkmint, I like here. = I like this place. I like it here = I like the (situation, circumstances, or general state of affairs) here. Other examples of 'it' meaning (situation,circumstances, etc.) How is it going? How is it in China? --------- I like here. This is a perfectly good English sentence. Example. Where would you like to have the party, here or in the park? Ans. I prefer here. ------- References: here....noun...this place. Webster's 11th Collegiate Dictionary. From the American Heritage Dictionary: n. here 1. This place: "It would be difficult from here, with the certainty of armed gunmen inside, to bring him out alive" (Howard Kaplan). 2. The present time or state: We are living in the here and can only speculate about the hereafter. and the Harper Collins Dictionary noun. here 1. this place They leave here tonight.

I like here is literally passable. Which means it's got an excuse to be grammatically right. And then, it just simply refers to some idiomatic use of English here.